The best science fiction and fantasy television hooks you with endless suspense... including hair-raising cliffhangers. But only the greatest cliffhangers can make you throw your remote at the screen, and keep you wondering for weeks. Here are the 20 awesomest.

After we did the best Doctor Who cliffhangers, we felt like we should do a round-up for all scifi/fantasy television shows — and we polled people via our Facebook page. Crowdsourcing works! (Oh, and a bunch of people named cliffhangers from shows that were canceled immediately afterwards, rendering those cliffhangers de facto endings. Maybe we'll do a separate list of just those "cancel-hangers" in a few days.)

Steven Moffat has promised the first half of Doctor Who season six will end on a cliffhanger that…
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Here are some of the cliffhangers you felt were the best, plus a few favorites of our own:

Warehouse 13, "Buried" Okay, maybe it's cheating to use a cliffhanger that just aired last night — but come on! H.G. Wells shot Pete and Myka! Plus Artie's been missing for way, way too long. And then there's the larger questions of just what H.G. wanted from that pyramid. It's going to be a long week...

Angel, "Tomorrow." Our ensouled vampire hero is stuck in a coffin under the ocean, and nobody even knows where he is — except his terminally misguided son, Connor. Meanwhile, Cordy is "ascending." How are they going to get around this? Hopefully the resolution won't involve an evil pregnancy... Oops.

Smallville, "Phantom." The kryptonite crystal doesn't even slow down the "Phantom" version of Clark — instead he just turns into the chalky-white Bizarro. Clark tries to stop him only to get knocked out of a dam, and Bizarro speeds off... probably to do something bizarre. Voted the greatest cliffhanger in this fan poll.

Red Dwarf, "Out Of Time". The Starbug crew gets into a battle with their own future selves, who are a bunch of obnoxious Hitler-loving snobs. And it ends with their future selves killing their past selves — this can't end well.

Star Trek: Voyager, "Basics, Part 1"Voyager may not exactly have been the greatest Star Trek show of them all, but this show definitely mustered some amazing cliffhangers, including the Borg-loving "Scorpion." But this was the best: the crew is stranded on a primitive planet, with no technology at all. Solve that, Janeway!

Jericho, "Why We Fight" The cliffhanger that gave Jericho fans their rallying cry, "Nuts!" — the first season ends with Jericho about to go to war with New Bern, as the remnants of the United States military rush to intervene. Guns blaze as the screen goes dark — thank goodness we got to see how this turned out.

Stargate SG1, "Camelot" Our heroes go into battle with the Ori, and it doesn't turn out well, with ships being shredded by the Ori's weapons. And meanwhile, Vala Mal Doran watches on board an Ori ship as her child, "the will of the Ori," is about to be born. People also praised season one's "Within The Serpent's Grasp."

Macross/Robotech, "The Messenger" Exedore tells the humans that the main Zentraedi fleet is on its way to Earth — but it's too late, as the fleet de-folds around our planet. Says Lynn Kyle, "You're crazy. A FLEET OF ALMOST FIVE MILLION!?!? There's no way we can fight them off. We're finished..."

Fringe, "Over There, Part 2" Poor, poor Olivia... not only is she trapped in the wrong universe, but she's locked in a cell by the more-sadistic, less-fragile Walter Bishop. And her possibly evil twin has taken her place on "our" Earth and is seeking "instructions"... eep.

Twin Peaks, "Beyond Life And Death". Okay, this is the only one we're including which is also the end of a series — Cooper's shattered reflection shows Killer Bob, the psycho serial killer, because Cooper has lost his soul and the good Cooper is apparently trapped in the Black Lodge. "How's Annie?" he asks over and over.

Doctor Who, "The Pandorica Opens" The entire universe is destroyed, plus Rory can't help shooting his beloved Amy. And the Doctor is sealed inside an escape-proof box for all eternity, knowing that he's failed to save everyone.

Lost, "The Incident" A bunch of people mentioned this one — I'm still somewhat annoyed by the way this played out, but I'll admit it was a great cliffhanger. Juliet blows herself up and there's a blinding white flash... can history be changed? Or is this what always happened? People also mentioned "We have to go back!" And a couple of people said the final episode was a great cliffhanger, what with the walking into the light.

The X-Files, "Duane Barry" Duane Barry believes he was abducted by aliens in 1985, and now he needs someone to take his place or the aliens will take him again. He gets shot, but escapes from the hospital — and then he breaks into Scully's apartment and kidnaps her. People also mentioned Mulder getting abducted while Scully's pregnant, at the end of season six.

Blake's 7, "Star One" Blake finally has the downfall of the evil Federation within his grasp — but then an entire fleet of alien ships shows up to invade our galaxy. Can one little ship defend against an entire invasion? "This is crazy!" Vila protests, and yet it's so right.

Supernatural, "Devil's Trap" Because Sam won't shoot his dad while he's possessed by the yellow-eyed demon, everything goes right down the tubes — in fact, that one mistake causes everything else in this show to happen. The Winchesters' car gets run off the road, and as they all pass out, a shadowy figure walks towards the car.

Battlestar Galactica, "Lay Down Your Burdens, Part 2" One of the most daring cliffhangers of all time — we jump forward a year, and suddenly everything's changed. And then the Cylons show up, when the humans are at their most domesticated and unprepared! Also notable: the endings of "Pegasus" and "Revelations."

Farscape, "Die Me, Dichotomy" Aeryn is dead, and Crichton blames himself. Not only that, but the surgery to fix Crichton leaves him aphasic and helpless, when Scorpius shows up and attacks the surgeon, leaving him unable to finish fixing Crichton. Scorpius leaves Crichton paralyzed, speechless and unable to take revenge, while Scorpius takes the memories on Crichton's chip.

Buffy season 2, "Becoming, Part 1" The Scooby Gang's plans don't exactly turn out as they'd hoped — vampires attack just as Willow is working on a curse, taking Giles prisoner and hurting Willow and Xander. Meanwhile, a cop finds Buffy standing over Kendra's dead body, leaving her framed for murder. People also mentioned Buffy dying at the end of season five.

Babylon 5, "Zha'dum" Sheridan hears Kosh's voice telling him to jump, and he does — just as the White Star crashes through the ceiling. All the Shadow ships vanish, because, as Ivanova says, "He's gone."

Star Trek: The Next Generation, "The Best Of Both Worlds, Pt. 1" And this is the cliffhanger most people mentioned, as well as arguably the best cliffhanger in television history. The episode does a great job of setting up the idea that Riker might be promoted as well as introducing a new XO, so you can believe that Picard might really be dying this time. (I would watch that show.) So when Picard is assimilated by the Borg, and Riker prepares to shoot his super-weapon at the Borg Cube... there's no telling what might happen.